The Microbiology Core for this program project grant application will provide standardized testing and expertise related to the effect of microbicides and exipients against Neisseria gonorrhoeae, Trichomonas vaginalis and normal flora organisms residing in the vagina and rectum including Lactobacillus species. The aims of the Microbiology Core are to; 1) support the first Project through the performance of vaginal and rectal cultures from primates prior to and after application of topical microbicide agents, 2) support the second Project through testing of the antimicrobial lipid octoglycerol and the antimicrobial peptides singly, and in combination, against N. gonorrhoeae, T. vaginalis and members of the normal genital flora, 3) Support the third Project by performing in vitro microbiologic assessments of candidate microbicides which would then be transferred to the third Project for toxicity and HIV testing, 4) support the fourth Project by providing testing of microbicide formulation excipients on viability of STD pathogens and members of the normal flora using standardized assays and 5) screen new candidate compounds for activity against Neisseria gonorrhoeae and Trichomonas vaginalis as well as Lactobacillus crispatus and other members of the vaginal flora. This activity serves as a entry point into the microbicide testing program with those compounds failing to have activity against at least one STD pathogen at concentrations not active against Lactobacillus being deferred from further testing. This core directly supports all the Projects and directly promotes development of topical microbicide development by providing standardized testing using a novel "exposure" assay system rather than standard susceptibility testing based on growth inhibition. This method has been validated during the present program project grant and has been found to be useful in predicting in vivo effects of microbicides on microflora.